The present invention relates to a connector terminal, particularly to a connector terminal that, when being fitted with a counter connector terminal, which has a flat plate shape and has top and bottom surfaces, along a fitting axis so that its contact portions corresponding to the top and bottom surfaces of the counter connector terminal come into contact with the top and bottom surfaces, enables the electric connection with the counter connector terminal to be established.
In electric wiring using, for instance, a wire harness for vehicles, a connector has heretofore widely been used which establishes the electric connection when a plug terminal in a flat plate shape is inserted into a socket terminal in a box shape so that the plug terminal is sandwiched from top and bottom between a plurality of contact portions of the socket terminal.
For instance, JP 2013-98088 A discloses a connector terminal in which a socket terminal 1 has three elongate convex contact portions 2A to 2C formed on an inner facing contact surface 2 and one dome-shaped embossed contact 3A formed on a resilient contact piece 3 and a flat plug terminal 4 is sandwiched between the elongate convex contact portions 2A to 2C and the dome-shaped embossed contact 3A, as shown in FIG. 11.
As shown in FIG. 12, the three elongate convex contact portions 2A to 2C of the socket terminal 1 are disposed on the inner facing contact surface 2 so as to be located at three vertices of a triangle, and the dome-shaped embossed contact 3A is located in a central portion of the triangle formed by the three elongate convex contact portions 2A to 2C and at a substantially equal distance from any of the three elongate convex contact portions 2A to 2C.
When the plug terminal 4 is fitted with the socket terminal 1, the elongate convex contact portions 2A to 2C of the socket terminal 1 come into contact with a top surface 4A of the plug terminal 4, while the dome-shaped embossed contact 3A of the socket terminal 1 comes into contact with a bottom surface 4B of the plug terminal 4, whereby the electric connection is established between the socket terminal 1 and the plug terminal 4.
In the connector terminal described in JP 2013-98088 A and shown in FIGS. 11 and 12, when the socket terminal 1 and the plug terminal 4 are fitted with each other, the dome-shaped embossed contact 3A formed on the resilient contact piece 3 of the socket terminal 1 comes into contact with the bottom surface 4B of the plug terminal 4, so that the plug terminal 4 is elastically pressed against the inner facing contact surface 2 of the socket terminal 1, and accordingly, a load is exerted from the top surface 4A of the plug terminal 4 to each of the three elongate convex contact portions 2A to 2C formed on the inner facing contact surface 2 of the socket terminal 1.
When loads acting on the three elongate convex contact portions 2A to 2C are unequal, the contact resistance between each of the elongate convex contact portions 2A to 2C and the top surface 4A of the plug terminal 4 varies, which may cause heat to be locally generated.